Japanese patent application JP-1990000281929 discloses the use of a liquid chromatography column filled with filler having weakly basic anion exchangeable radical for analyzing saccharide (monosaccharide or oligosaccharide). The filler has first class amino radical, second class amino radical and/or third class amino radical. The column is first eluted with 0.1 N HNO3 water solution and then the column is eluted with absolute methanol.
U.S. Pat. No. 5,482,631 discloses a method for separating inositol from sugar and sugar alcohols. The method comprises a resin, which comprises a strong base anion exchange resin in chloride form. The method is performed in a simulated moving bed chromatographic system.
Tanaka H. et al. describe in their article “Determination of Component Sugars in Soil Organic Matter by HPLC” in Zentralbl. Mikrobiol. 145(1990), 621-628, a method for determining component sugars of soil carbohydrates. In the method a column of strong-base anion exchange resin was used and glucose, galactose, mannose, xylose, rhamnose and ribose were separated. However, arabinose, fucose and fructose were eluted in the same peak and they could not be separated from each other.
U.S. Pat. No. 6,153,791 discloses a process for the purification of 2-keto-L-gulonic acid by continuous liquid chromatography using a weakly basic ion exchanger. According to the publication the weakly basic ion exchange resin comprises anionic exchange resin having pyridine functionality. However, the method is only capable of separating 2-keto-L-gulonic acid from sorbose and therefore sugars cannot be separated from each other with this method.
Paskach, T. et al. have described in their article “High-performance anion-exchange chromatography of sugars and sugar alcohols on quaternary ammonium resins under alkaline conditions” in Carbohyd. Res. 215 (1991)1-14, the use of strongly basic high performance liquid chromatography with quaternary ammonium resins to separate sugars and sugar alcohols.
Murphy, P. T. et al. have stated in their article “A reversible reaction between reducing sugars and a weak-base anion-exchange resin” in Carbohyd. Res., 7 (1968) 460-467, that caution should be exercised in using a weak-base anion-exchange resin in the presence of reducing sugars. According to the article it is well known that contact between a strong-base anion-exchange resin and reducing sugars leads to epimerisation and irreversible sorption. In the article it is shown that in attempts to use weak-base anion-exchange resins in the presence of free sugars, the researchers have frequently detected significant losses of neutral sugars. In the article it is shown that the effect is caused by the reversible formation of a covalent compound between the resin and the reducing sugar.
WO publication 00/42225 describes a method for separating sugars while still allowing ready desorption from the resin. The method comprises the use of a strong base anion exchange resin in chloride form. The resin has been conditioned with a sufficient concentration of hydroxyl ion.
Bilik, V. et al. in their article in Chem zvesti 33 (1) 118-122 (1979) have described the separation of ketoses and aldoses with polyethyleneimine ion exchanger in the Cl or OH form eluted with water. With the method described 9 ketoses and 14 aldoses were separated. However, the ketoses and aldoses cannot be separated from each other. Also the manufacture of spherical particles, starting from polyethyleneimine and epichlorohydrin, is more difficult compared with conventional starting materials like styrene, acrylates, acrylonitrile and divinylbenzene. Ethyleneimine is also considered to be quite hazardous material.
Lindberg B. et al. in Carbohyd. Res. 5 (1967) 286-291, have studied the use of strongly basic anion-exchange resin in the bisulphite form for the preparative separation of sugars. The utility of the bisulphite-column method was demonstrated not only by the separation of ketoses from aldoses but also by the preparation of chromatographically pure D-fructose, D-glucose and D-galactose from commercial products.
Oshima R. et al. have studied separation of anomers of saccharides by strongly basic macroreticular anion exchange resin in the sulphate form. The resin has a relatively high degree of cross-linking. The method is carried out at room temperature and the eluant is ethanol-water solution (80%/20%). The experiments showed that the higher percentage of ethanol enhanced the separation. 2-deoxy-ribose, rhamnose, fucose, galactose, xylose, mannose, fructose, sorbitol, galactose, glucose, lactose, maltose, sucrose and raffinose were separated by the process.
Bauer and Voelter have described an analytical separation technique for carbohydrates in Chromatographia, Vol 9, No 9, September 1976. According to Bauer and Voelter sugars react with boric acid to form anionic complexes and are as such separable on strongly basic ion-exchange resins. In the method optimisation of the conditions of separation and detection allowed the separation and detection of 10 sugars to take place faster than with the previous methods.
Brown, W. has described the selectivity of polyacrylamide gel adsorbents for sugars in the article in J. Chromatog. 53 (1970) 572-575. The resin used in the method is a polyacrylamide resin, and the sugars separated by the process are raffinose, sucrose, rhamnose, galactose, glucose, fructose/mannose and xylose. However, the amide groups of polyacrylamide do not possess ion exchange capacity.
Malan, A. et al. have described in their article in Ann. Fals. Exp. Chim., July-August, 1988, 81, no 869, pp 275-281, a method for separating for example sucrose, maltose, lactose, mannose, fructose, arabinose, xylose, glucose and its invertsugars with a strongly basic anion exchange resin.